1. Field of the Invention
The invention relates to a method and device for the cooking and vacuum packing of food by the use of microwaves, such that said food can be stored as chilled or frozen goods.
2. Background Information
Generally, all kinds of food that don't require browning, e.g., using a frying pan, can be cooked in microwave ovens. This is common knowledge today, and can be seen in the multiple microwave cook books available on the market. See for example “Easy cooking for today”, Martin, Pol., Brimar Publ. Inc., 1995, Montreal. However, foods that require browning can initially be browned in a traditional way and thereafter cooked in a microwave oven.
“Microwave and radio frequency heating for pasteurization and sterilization are preferred to the conventional heating for the primary reason that they are rapid and therefore require less time to come up to the desired process temperature. This is particularly true for solid and semi-solid foods that depend on the slow thermal diffusion process in conventional heating. They can approach the benefits of high temperature-short time processing whereby bacterial destruction is achieved, but thermal degradation of the desired components is reduced. Industrial microwave pasteurization and sterilization systems have been reported on and off for over 30 years Studies with implications for commercial pasteurization and sterilization have also appeared for many years. As of this writing, 2 commercial systems worldwide could be located that currently perform microwave pasteurization and/or sterilization of foods (in the year 2000). Though continuous microwave heating in a tube flow arrangement has been studied at the research level, no commercial system is known to exist for food processing.” (U.S. Food and Drug Administration, Center for Food Safety and Applied Nutrition, Jun. 2, 2000. Kinetics of Microbial Inactivation for Alternative Food Processing Technologies. Microwave and Radio Frequency Processing.)
The known commercial systems are Tops in Belgium and Akiyama in Japan where the former uses a non-continuous pressurized tunnel for sterilization of ready meals in closed plastic trays. The over-pressure in the sterilization tunnel prevents the plastic trays from exploding when the temperature inside the trays exceeds 100° C.
As the foregoing FDA article points out, there are advantages of microwave technology in food processing, but still there are very few industries in the world using this technology because it is complicated and expensive.